On Wed, Jun 29, 2011 at 10:52:48PM +0800, Wu Fengguang wrote:

The estimation value will start from 100MB/s and adapt to the real
bandwidth in seconds.

It tries to update the bandwidth only when disk is fully utilized.
Any inactive period of more than one second will be skipped.

Is this piece of code being tested in your graphs? Are there any
inactive periods which get filtered out in your workload? I am 
assuming in a continuous dd, we will not have periods of inactivity
1 second long.

Thanks
Vivek